Malaysian Society of Soil Science

Abstract
Conserving tropical peat forests with high carbon density is among the most cost-effective strategies for addressing global climate change. However, large areas of these forests have historically been impacted by land-use changes, logging, and other human activities, leading to substantial carbon emissions into the atmosphere. This study quantified the physico-chemical properties and soil carbon stocks in a total of nine (9) different compartments representing three (3) different categories of forest; which were high, medium and low density forest located in the district of Rompin, Pahang in order to assess the differences between them. Collected samples were analysed for the physical characteristic; bulk density, total porosity, moisture content and chemical properties; ash content, loss of ignition and organic carbon content. The results showed minimal variation, with most parameters exhibiting similar trends across all densities. Consistency in pH, bulk density, moisture, organic carbon content, and loss on ignition indicates that, despite varying forest densities. The soil carbon stock for the high, medium and low density forests were 329.48 ± 62.25 (C t/ha) 328.50 ± 64.71 (C t/ha) 326.46 ± 48.79 (C t/ha), respectively. Statistical analysis by using ANOVA followed by multiple mean comparison showed no significance difference were observed among the carbon stock value between the three categories of forest. Comprehensive understanding of the variability of the peat properties within the studied area is essential for developing effective strategies for their conservation and sustainable management.

Abstract
In Laos, where chemical fertilizers are costly and organic matter is underutilized, agricultural waste compost often lacks the nutrients needed for effective soil enrichment. Teak wood sawdust, a byproduct of expanding smallholder teak plantations, is abundant yet remains largely untapped as a compost component. This study evaluated the effectiveness of agricultural waste, specifically sawdust (S) and manure (M), fermented with Rhizobium microorganisms (RM) to enhance compost quality. The objective was to compare the chemical composition of compost arranged in a completely randomized design with 5 treatments and 4 replicates. Treatments evaluated were: T1) S and M (50:50); T2) S and M (50:50) + RM soybean; T3) S and M (50:50) + RM mung bean; T4) S and M (50:50) + RM sunn hemp; T5) S and M (50:50) + RM liquid culture of mung bean. Sawdust and manure were mixed and fermented with 2% Rhizobium, placed in plastic bags, and kept indoors for 45 days. Chemical analyses included DM (dry matter), pH, N₂, P₂O₅, K₂O, OM (organic matter), and ash. Results indicated significant differences (P<0.05) in chemical compositions: pH was highest in T3 (7.18), OM in T4 (33.08%), N₂ in T2 (0.17%), P₂O₅ in T3 (0.36%), K₂O in T2 (0.94%), DM in T4 (59.81%), and ash in T1 (2.45%). Among treatments, RM combined with soybeans emerged as a promising solution to enhance compost nutrient content. These findings support the potential for RM-enriched compost to improve soil fertility sustainably, offering an accessible soil amendment for farmers in resource-limited settings.

Abstract
In response to the increasing costs, decreasing efficiency of nitrogen fertilizer use, and arsenic-contaminated soil leading to reduced crop yield and quality. The agricultural community has actively looking for sustainable alternatives to exploit the natural nitrogen source from biological N fixation, lime and cow manure supplementation to improve crop yield and quality. This study investigated the combined effects of Indigenously Endogenous Nitrogen Bacteria (IENB) and its combination with cow manure (CM) and lime on soil fertility, available nutrients as well as yield and quality parameters of white bean. The study included the application of lime rates (0 and 3.0 CaCO₃/ha); CM (0 and 5.0 t/ha) combined with Bacterium strain BS1897 species on "BI" variety of white bean, using a complete factorial design with 4 treatment levels and 4 replications. The results showed that the application of lime, CM, and Bacterium strain NTLG2-5 (B. NTLG2-5) to the soil had a positive effect on white bean plants. The fresh seed yield significantly raised to compare to the control treatment, which ranged from 17.0 to 33.0%. The As accumulation of white bean stems decreased significantly from 21.3 to 65.8% compared to the control treatment. In particular, there was no As accumulation of white bean seeds in all treatments. The addition of lime and CM, either separately or in combination, fully improved plant yield and quality. Therefore, it is necessary to apply lime, fertilizer, and indigenous IENB inoculation in combination to increase crop yield and improve crop quality on the As contamination soil and irrigation water.

Abstract
Mercury (Hg) contamination of ex-gold mining soils is of particular concern as it affects the availability of nutrients in the soil such as phosphorus (P). The nteraction of Hg with P in soil needs to be studied quantitatively through amelioration technology that is expected to control Hg in the soil system. The purpose of this research is to study and analyze the correlation of Hg and P in ex-gold mining soil ameliorated with sub-bituminous coal and the activation of sub-bituminous coal with NaOH. The experimental design used in this study was a completely randomized design (CRD) with three (3) replications. The treatment I (Sub-bituminous coal) and II (activation of Sub-bituminous coal with 10% NaOH) was implemented in the pot with equivalent doses, respectively: (A) 0 [0g 100g^-1 soil], (B) 10 [0.5g 100g^-1 soil], (C) 20 [1g 100g^-1 soil], (D) 30 [1.5g 100g^-1 soil], and (E) 40 t ha^-1 [2.0g 100g^-1 soil]. The correlation and equation of linear regression between total Hg with Available P on ex-gold mining soil ameliorated with sub-bituminous coal [r = -0.922** and Hg = -0.206 (PO₄^-) + 7.0068; R² = 0.9052] and activation of sub-bituminous coal with 10% NaOH [r = -0.862** and Hg = -0.0265 (PO₄^-) + 6.2774; R² = 0.7851]. Amelioration technology on ex-gold mining soil with sub-bituminous coal and activation of sub-bituminous coal with 10% NaOH can reduce the total Hg by 2.50 and 2.84 mg kg^-1 and also increase the available P by 11.88 and 76.91 ppm PO₄^- respectively, compared to control.

Abstract
Utilizing spent coffee grounds for compost production presents an avenue to mitigate environmental issues. Converting spent coffee grounds into compost helps improve soil properties, enhancing soil structure stability, reducing compaction, enhancing water retention, and improving soil chemical properties. From the experiments conducted, it was observed that the production of compost from coffee grounds resulting from experiments 1 to 6 can effectively reduce the volume of organic waste, providing a sustainable use for this leftover material. The decomposition process consisted of two stages. The initial stage involved the decomposition by a group of mesophilic bacteria, taking approximately 2-4 days to reach a higher temperature range of 60-70 °C Subsequently, the decomposition of organic matter was facilitated by a group of thermophilic bacteria, with the temperature gradually decreasing to around 25-30 degrees Celsius, which closely approximated the ambient temperature of the compost pile. Overall, the decomposition process took between 80-90 days. Over an 80–90-day composting period, the process achieved optimal conditions, with moisture content ranging between 31.66-34.50%, electrical conductivity values of 0.71-0.79, pH levels between 6.60-7.51, and a carbon to nitrogen ratio of 16.78-18.56%. The compost's nutrient composition included nitrogen (1.43-1.80%), phosphorus (0.54-0.68%), and potassium (0.71-0.80%), adhering to the standards set by the Department of Agriculture, Thailand. Application of this compost significantly improved the growth of Brazilian spinach, evidenced by enhanced canopy width, branch number, plant height, and total weight, with statistical significance (P<0.05) compared to control groups. This study not only presents a sustainable approach to managing coffee waste but also provides insights into effective organic fertilizer production for agricultural use. When the compost was tested for its effectiveness on Brazilian Spinach growth, it was found that all experiments had a statistically significant impact (P<0.05) on the width of the canopy, number of branches, plant height, and total weight. Notably, the experimental set using 100% coffee grounds (control) resulted in the smallest average measurements for canopy width, number of branches, plant height, and total weight.

Abstract
The decomposition process of a partially submerged-buried body is not well understood causing difficulties in locating of a partially submerged clandestine grave. In order to address the influence of the excessive moisture on the decomposition of a cadaver, therefore, a simulated burial experiment was performed using fatty flesh of commercial pig (Sus scrofa). The fatty flesh was shallowly buried in mangrove soil system that consistently experiencing low and high tides. The fatty flesh was allowed to decompose for 120 days, and the associated soils were collected at 16 designated sampling points. The decomposition rate and soil post-experimentalsoil pH were measured. Whilst the soil cadaveric derived lipids were extracted using modified Bligh Dyer extraction method and analysed with Gas Chromatography Flame Ion Detector (GC-FID) to establish the lipid distribution profile for each of the decomposition stages. The post-experimental soil pH increased to be more alkali at the early decomposition stages and became acid towards completion of experiment. Similar trend was also observed for decomposition rate, with a rapid incline after day 3 of burial interval. The distribution of extractable lipids was different for different decomposition stages, with massive introduction of the lipids into the soil was observed between the initial and black putrefaction stages. The observed physicochemical changes of soil pH, decomposition rate and distribution of cadaveric derived lipids shall provide useful information to aid in locating the partially submerged clandestine grave, subsequently, to determine the postmortem interval of the deceased.

Abstract
The quality of the plant growth medium (PGM) is crucial for the growth of horticultural plants, yet a common issue with PGM is its high electrical conductivity. Zeoponics, which uses zeolite as a base material often combined with compost, cocopeat, and fertilizers, helps mitigate this issue. However, Zeoponics still requires frequent watering due to limited water absorption. This research explores the incorporation of super absorbent polymer (SAP), known for absorbing 200 to 400 times its weight in water, to address this limitation. The study aimed to determine the optimal SAP quantity and assess plant survival duration with a new blend, termed zeoponic super absorbent (ZSA). Green mustard plants were used as indicators, with growth parameters such as height, fresh weight, and dry weight measured. Various ZSA blends were prepared with different SAP waste percentages (0%, 0.2%, 0.4%, 0.6%, 0.8%, and 1%). Results indicate that increasing SAP concentration improves soil water retention and field capacity. The ZSA blend with 1% SAP content exhibited the highest air-dry moisture content (71.92%) and field capacity (205.5%), reducing the watering frequency to approximately once every 21 days. Additionally, optimal plant growth parameters, including height, leaf width, leaf length, and stem diameter, were observed at the 1% SAP concentration. The highest fresh weight (58.60 g) and dry weight (14.72 g) were observed at 1.0% SAP (ZSA5), indicating optimal biomass growth at this concentration. These findings suggest that integrating SAP into Zeoponics can significantly enhance water retention, improve plant growth, and increase drought resistance. This offers a practical solution for agricultural practices in water-stressed environments.

Abstract
Gunung Bromo Education Forest is a forest that functions as a buffer area to maintain the balance of the surrounding area. However, the undulating to hilly topography, the presence of rivers, and land management for annual crops can make the area vulnerable to erosion-induced degradation. This research aims to analyze and classify the erosion hazard level in Gunung Bromo Education Forest and analyze the relationship between research parameters and erosion in Gunung Bromo Education Forest. Erosion was predicted using the MUSLE method. This research used an explorative-descriptive method incorporating a survey and laboratory analysis. Furthermore, data analysis used was Analysis of Variance (ANOVA), Duncan’s Multiple Range Test (DMRT) at a 5% significance level, and Pearson correlation test. The results showed that Gunung Bromo Education Forest erosion ranged from 0.025 to 78.36 t ha^-1 y^-1. The erosion hazard level in Gunung Bromo Education Forest is in the very light to heavy class and is dominated by the light class. The factors of erosivity (R), erodibility (K), slope (LS), and crop management (C) are positively correlated with erosion values. The conservation factor (P) is negatively correlated with erosion values. Making remedial efforts according to the erosion hazard level is important to avoid greater damage.

Abstract
Soil erosion is a prevalent issue causing land degradation worldwide. This study aims to determine the spatial distribution of annual soil erosion through the utilization of the Revised Universal Soil Loss Equation (RUSLE) model in Quetta sub-basin, situated in the southwestern region of Pakistan. To accomplish this, numerous data mining techniques were employed, along with machine learning algorithms, to produce thematic layers (R, K, LS, C, and P) that served as input parameters for the RUSLE model. According to the resultant model, soil erosion in the study area ranged from 0.00 to 866 tons per hectare per year. The estimated values for rainfall-runoff erosivity (R), soil erodibility (K), topography (LS), and cover management (C), factors ranged from 147 to 191 (MJ.mm.ha⁻¹.h⁻¹ year⁻¹), 0.0229 to 0.0259 (t.ha.MJ⁻¹mm⁻¹), 0.002 to 360.77, and 0.001 to 1, respectively. The statistics revealed that 58% of the land in the study area experiences a very low degree of soil erosion, with an erosion rate of less than 13.58 t/ha/year. About 24% of the study area faces low erosion, with an erosion rate spanning from 13.58-44.16 t/ha/year. 13% of the area is demarcated as moderate soil erosion severity, at an erosion rate ranging from 44.16-81.53.14 t/ha/year. On the other hand, 5% of the study area experienced high to very high soil erosion, with an erosion rate of 81.53-866.34 t/ha/year. The northern part (Takatu range), north-eastern part (Zarghoon range) eastern-central (Murdar range), and western-southern (Chiltan range), which are characterized by steep slopes and barren land, experience high to very high severity of soil erosion. Decisively Remote Sensing and GIS, in combination with the RUSLE model, are significant for identifying input factors for modeling soil erosion and resource management. This study will provide firsthand guidance to assist policy/decision-makers and planners in pinpointing the erosion-prone areas that urgently need soil conservation measures.

Abstract
This study was conducted in the Manten Sub-Watershed Catchment Area, Malang Regency, focusing on the districts of Bululawang, Tajinan, Wajak, and Poncokusumo. The research assessed three land use types—plantations, rice fields, and gardens—each represented by five sampling sites to capture the variation in land use across the region. Results revealed that garden soils exhibited superior chemical health compared to rice fields and plantations. Key soil limitations identified included low organic carbon content, cation exchange capacity (CEC), and base saturation (BS), all of which were found to restrict soil fertility in the study area. These findings highlight the urgent need for targeted soil management practices to enhance land productivity and promote sustainable agricultural practices in the region.

Abstract
The study was carried out to evaluate the effects of combining Gluconacetobacter diazotrophicus bacteria and reduced nitrogen (N) fertilizer on rice growth, grain yield, and soil properties. The field experiment was conducted at the triple rice cultivation in the Vietnamese Mekong Delta region. It was laid out in a split-plot design, with G. diazotrophicus as the primary parameter and different N fertilizer rates as the sub-factor. Two methods were applied for rice seeds included: inoculation with G. diazotrophicus (Gd) and without G. diazotrophicus (Go). Four N fertilizer rates: 0 kg N ha^-1 (N0), 50 kg N ha^-1 (N50), 75 kg N ha^-1 (N75), and 100 kg N ha^-1 (N100). The study results revealed that applying G. diazotrophicus combined with reduced N fertilizer can maintain the tiller number, height, biomass, and grain yield, while significantly increasing the SPAD value. Furthermore, the combination of G. diazotrophicus with reduced N fertilizer resulted in a significant increase in the soil pH, NH₄⁺-N, and available phosphorus. In contrast, soil EC, soil organic matter, and total N were maintained. Further research on the applying G. diazotrophicus bacteria combined with reduced N and P fertilizers to enhance soil characteristics, and improve N use efficiency, and grain yield in the Vietnamese Mekong Delta region is recommended.

Abstract
Several microorganisms that encourage plant growth possess the capacity to redox atmospheric dinitrogen, which can be employed in sustainable crop production to reduce the need for nitrogen (N) fertilizer. Tomatoes receive a lot of N fertilizer application (Lycopersicon esculentum). Therefore, applying PGPB, a nitrogen-fixing microbial inoculant, will help reduce the use of inorganic fertilizer on tomato plants. This study aimed to test the hypothesis of whether the application of PGPB will reduce the amount of nitrogen fertilizer required by tomato plants. Therefore, the microbial inoculants used were Bacillus subtilis (UPMB10) and Bacillus tequilensis (UPMRB9) at different N fertilizer levels. To lower the nitrogen fertilizer requirement for tomato plants, a glasshouse pot experiment was carried out with the chosen microbial inoculants and nitrogen fertilizers at varied levels (0% N, 50% N, and 100% N). The pot experiment's findings indicated that microbial inoculation increased plant growth, dry weight, physiology, tissue N concentrations, and bacterial population in rhizosphere soil when N fertilization was present. Additionally, the findings revealed that reducing 50% of the prescribed N fertilizer through microbial inoculation does not affect tomato plant growth, nutrition, and development. Future field research must ascertain whether these inoculants may be used as biofertilizers in agriculture nutrient management techniques.

Abstract
Tropical forests in Sarawak are characterized by high biodiversity and complex interactions between soil properties and tree growth. In logged forests, where optimal economic cut decisions are critical for both sustainability and economic return, soil fertility emerges as a key determinant of growth performance. This study investigated the relationship between soil quality and the growth dynamics of Shorea angustifolia across three forest management areas in Sarawak: Lambir Hills National Park, Gerenai Forest Management Unit, and Mujong-Melinau Forest Management Unit. Tree growth data, including age and diameter at breast height (DBH), were obtained from historical inventories and current field measurements, and a negative exponential growth model was applied to predict the optimal harvest age for the species. Concurrently, soil samples were collected from each site and analyzed for pH, total organic carbon, total nitrogen, available phosphorus, exchangeable cations (Ca, Mg, K, Na), cation exchange capacity, base saturation, and were summarized using a Tropical Soil Quality Index (TSQI). The results revealed a clear fertility gradient among the sites: Lambir exhibited the highest TSQI and nutrient levels, which corresponded with a lower predicted harvest age (75.4 years), while Gerenai, with lower soil fertility, had a higher predicted harvest age (85.0 years); Mujong-Melinau displayed intermediate values. Significant negative correlations were observed between TSQI, available phosphorus, and total organic carbon with the predicted harvest age, indicating that improved soil fertility accelerates tree growth. These findings underscore the importance of incorporating soil quality assessments into growth models to refine optimal harvest age predictions and develop site-specific management guidelines for sustainable timber production.

Abstract
Supplementing chemically fertilized soil with biochar might enhance plant growth and decrease fertilizer needs. Biochar could impact not only the initial cropping cycle but also subsequent cycles, even without additional applications. Seven soil amendments were investigated: unamended, 100% of the recommended chemical fertilizer (100%CF), 50%CF+eucalyptus biochar (EUB), 100%CF+EUB, 50%CF+rice husk biochar (RHB), and 100%CF+RHB. Corn was used as the plant bioassay over three cropping cycles, with biochars applied only before the first cycle. Biochar supplementation generally had a negative effect on plant growth, so more EUB than RHB. The effects of biochars were classified into two phases. The first phase showed an immediate negative effect during the first two cropping cycles. Compared to 100%CF, the 50%CF+EUB decreased corn shoot biomass by -35.8% and -26.9% (1st and 2nd cycles); 100%CF+EUB by -13.7% and -20.2%; 50%CF+RHB by -34.8% and increased by +5.2%; and 100%CF+RHB decreased by -3.4% and increased by +72.1%. The second phase showed a delayed negative effect in the third cycle, with depression in corn shoot biomass of -51.8% and -47.4% for 50%CF and 100%CF+EUB, and -15.2% and -23.7% for 50%CF and 100%CF+RHB.

Abstract
Tropical forests provide critical ecosystem services, yet anthropogenic disturbances, particularly selective logging and land conversion, threaten soil quality and forest productivity. However, the exact impacts of this study on soil quality has not been adequately explored in tropical forests. Thus, this study evaluated topsoil (0-20 cm) physical and chemical properties and overall soil quality using the Tropical Soil Quality Index (TSQI) in natural forests, logged forests, and forest plantations in Kuala Kubu Bharu, Malaysia. A stratified random sampling approach was employed, with composite soil samples collected from 18 plots (six per forest type). Soil analyses included measurements of bulk density, coarse fragment content, pH, organic carbon, total nitrogen, and nutrient availability. Results revealed that natural forests maintained significantly better soil conditions, evidenced by lower bulk density (0.95 ±0.05 g/cm³), higher organic carbon (2.44 ±0.17%), and robust nutrient retention (CEC: 10.75 ± 0.11 cmol/kg) culminating in a TSQI of 60%. In contrast, logged forests exhibited severe degradation, with increased bulk density (1.55 ±0.18 g/cm³), elevated coarse fragment content (58 ±3.4%), and diminished nutrient levels, reflected by a TSQI of 13.33%. Forest plantations demonstrated intermediate characteristics with a TSQI of 46.67%. These findings underscore the need for sustainable forest management practices, including reduced-impact logging, targeted post-logging restoration, and improved silvicultural strategies in plantations. Future research should focus on refining the TSQI and incorporating seasonal and spatial variability to further inform adaptive management and optimal economic cut decisions in tropical forest ecosystems.

Abstract
The Soil Color Detector Version 1.0 (SCD V1.0) has been developed to improve both accuracy and efficiency in soil color identification through the integration of optical sensor technology and the utilization of the RGB color index as referenced in the Munsell Soil Color Chart (MSCC). The system underwent extensive testing across various soil types in Indonesia, specifically Ultisols (Baregbeg), Inceptisols (Cilembu), and Andisols (Lembang), as well as subtropical Chernozems (Mollisols) in FH-Erfurt, Germany. The presence of significant differences among the results obtained from the SCD V1.0, the MSCC manual method, and the MetaVue VS3200 spectrophotometric analysis, paired t-tests and analysis of variance (ANOVA) were conducted. The results demonstrated a remarkable accuracy of 100% for soil color name diagram and color index accuracy rates reaching up to 99%. Root Mean Square Error (RMSE) analysis revealed reduced deviations when comparing SCD V1.0 to the MetaVue VS3200 instrument (0.6-0.9), as opposed to comparisons with the MSCC (0.9-1.2), indicating a higher degree of precision in optical-based classifications. Furthermore, reproducibility assessments indicated lower standard deviations for SCD V1.0 (0.10-0.15) in contrast to the MSCC (0.25-0.32), with a strong agreement coefficient of 0.85 across all evaluated soil orders. These results substantiate that SCD V1.0 presents a reliable automated alternative to conventional manual methods of soil color identification, thereby minimizing human error and reducing environmental variability. The implications of this technology are particularly pertinent in soil color identification application for soil classification studies, survey & land evaluation, and digital soil mapping (DSM), especially within tropical and subtropical regions.

Abstract
This study investigated the morphological and physicochemical characteristics of sandy soils under horticultural monoculture on the erosional slopes of Mount Gamalama Volcano, Ternate Island. Volcanic activity of Gamalama Volcano has contributed to the formation of young sandy soils, which are often characterized by rapid weathering and low fertility. The region is dominated by steep topography, and the history of active volcanoes further complicates soil management. In addition, intensive horticultural monoculture with 2-3 month crop rotations exacerbates soil fertility degradation, leading to erosion and nutrient loss. Given the challenges posed by these conditions, there is an urgent need to understand soil physical and chemical properties to develop effective land management strategies. We created three soil profiles located in the erosional zone of a regional slope of Mount Gamalama. Soil profile observations were made by characterizing soil morphology, and then at each soil depth, detailed soil physicochemical property parameters were analyzed according to USDA standards. The results showed that soils on the erosional slopes of Gamalama have low fertility and poor water holding capacity, which significantly limits agricultural productivity. In addition, the lack of organic matter and high susceptibility to erosion exacerbate the degradation process. These findings highlight the critical need for improved agricultural management techniques.

Abstract
Soil compaction is a major challenge in modern agriculture, reducing soil quality, restricting crop growth, and decreasing the efficiency of agricultural machinery. Factors such as soil texture, organic matter, and soil moisture during machine trafficking are key contributors to compaction and must be effectively managed to sustain soil health. This study investigates the potential of organic matter (OM), specifically cow manure, to mitigate soil compaction in sandy clay loam soils. The research examines three moisture levels (9.40%, 13.59%, and 16.99%) and four compaction energy levels (2475, 7425, 12375, and 56000 ft-lb/ft³), with OM applied at a 5% concentration at three depths (0 cm, 4 cm, and 8 cm). Two compaction methods, the Modified Proctor Test and the Agricultural Engineering Test, were employed. Results show that increased compaction energy directly correlates with higher soil bulk density, with rises of 27.95% and 33.08% at the highest energy levels. Moisture content significantly influenced bulk density, with increases of 6.84% and 11.99% observed in the Agricultural Engineering and Modified Proctor Tests, respectively. Surface-applied OM resulted in the lowest bulk density across both methods. These findings highlight the effectiveness of organic matter in alleviating soil compaction and improving soil structure. Optimizing OM application and managing soil moisture are practical strategies for enhancing agricultural productivity and promoting sustainable soil management.

Abstract
Crop production is one of the most important economic activities worldwide and a pillar in achieving food security. One of the different alternatives that have been studied to improve it as well as to reduce its impact on the environment is the substitution of inorganic fertilizers with organic amendments. This study aimed to evaluate the impact of the use of biomass from three different legumes on soil characteristics and the production of barley. To test this, a greenhouse experiment was used to grow barley in soil amended with biomass from alfalfa, soybean, and bean as a single species or a combination of them (biomass of fully grown plants from 30 g seeds). After soil amendment, barley was grown, testing each treatment over 15 weeks through overall growth, amount of grains per spike, and the number of spikes. Moreover, the impact of the amendments on soil characteristics was also evaluated. Results showed that the different amendments significantly modified both soil characteristics and the overall production of barley. Soil organic matter (3.32 %) and organic carbon (1.92%) were significantly higher when soil was amended with a combination of alfalfa and soybean. Further to this, this same treatment consistently produced the largest production and overall plant growth. Based on these results, it can be concluded that the use of plant biomass as an amendment has a significant influence on increasing the total length of barley as well as the number of spikes and seeds per spike while modifying quality.

Abstract
The optimization of soil microbes as biological agents in biofertilizers plays a crucial role in enhancing plant production. One of the primary functions of biofertilizers is biocontrol, which can be optimized by adding natural antibiotics, such as azadirachtin compounds from neem plants. Additionally, biofertilizers' effectiveness can be enhanced by improving their spreadability on plants and growing media. Palm olein-based diethanolamide (DEA) biosurfactant, a derivative of palm oil, has the potential to serve as a biofertilizer carrier while also enhancing its spreadability. This study aims to evaluate the viability of a bacterial consortium isolated from the rhizosphere at various propagation stages and after adding neem extract and DEA biosurfactant. It began with the rejuvenation of isolates from a previous study, followed by bacterial population testing at each propagation stage—200 mL, 1000 mL, and 5000 mL—to ensure optimal microbial populations before applying additional treatments. Additionally, chemical characterization tests were conducted to assess the quality of the resulting biofertilizer. The results showed that the total microbial population during isolation and propagation met the standard microbial population threshold, with an average colony count above 10⁷ CFU. The combination of biofertilizer with neem extract resulted in a bacterial population of 7.495 × 10⁹ CFU. However, chemical characterization tests indicated that the tested parameters did not meet the biofertilizer standards set by Indonesia's Ministry of Agriculture Regulation No. 261/KPTS/SR.310/M/4/2019.

Abstract
The agronomic use of glyphosate as a weed killer has great potential as a form of contaminant in soil and crop systems. This study aims to assess the effect of glyphosate contamination on soil chemical properties and shallot production in Inceptisols ameliorated with geo-biomaterial. Geo-biomaterials based on sub-bituminous coal (SC) and three types of biochar (B) namely rice husk (RH), young coconut waste (YCW), and bamboo (Ba), where there are five formulations with a percentage of 100% SC; 75% SC+25% B; 50% SC+50% B; 25% SC+75% B, and 100% B ⁓ 40 t ha-1 and control (without geo-biomaterials). Then, there are three experiments, namely E1 (SC+B-RH); E2 (SC+B-YCW), and E3 (SC+B-Ba) using a completely randomized design (CRD) with three replications. The impact of glyphosate contamination significantly changes the chemical properties (pH, CEC, organic C, total N, available P) and shallots production (fresh and dry weights of bulbs and N, P, and K-plant) in Inceptisols ameliorated with geo-biomaterial. Geo-biomaterials from the formulation of 75% SC and 25% B, can increase OC, available P, and bulb dry weight (SC+B-RH); OC, bulb fresh weight, and P-plant (SC+B-YCW) and total N, available P, K, and P-plant (SC+B-Ba) and also proved effective in overcoming glyphosate residues (GR) in Inceptisols soil and reducing GR bioavailability in shallot plants, compared to the control. Application of 75% SC+25% B can provide a multifunctional solution to improve waste optimization, soil, and plant productivity, and at the same time reduce the negative impact of residual pesticides on agricultural land.

Abstract
Irrigation with brackish water is a common practice in coastal Odisha during winter and summer season because of scarcity of good quality irrigation water. Soil salinity developed with brackish water irrigation affects root growth and nutrient availability due to osmotic stress and ion toxicity. The adverse effect of salinity can be mitigated through application of phosphatic and zinc fertilizer. With this hypothesis we tried to evaluate the effects of phosphorous and zinc on electrical conductivity of saturated paste (ECe), nutrient availability and root growth of maize irrigated with normal water (SW₀- EC 0.6 dS m^-1) and brackish water (SW₁- EC 8 dS m^-1). The maize received four levels of P fertilizer (P₁ - 15 mg P kg^-1 soil basal; P₂ - 30 mg P kg^-1 soil basal; P₃ - 30 mg P kg^-1 in two splits and P₄ - 45 mg P kg^-1 in two splits) and two levels of zinc (Zn₀ - zinc control and Zn₁ - nano zinc 5% @ 1.25 mg kg^-1 soil). Brackish water irrigation (SW₁) significantly (p≤0.05) increased the soil ECe (212%), available phosphorus (70%) and sodium (250%) but decreased the organic carbon, available Ca, Mg and DTPA Zn by 18,14, 16 and 3% respectively over SW₀ treatment. The root length, root weight, root volume, root density and CEC of roots in SW₁ treatment were decreased by 36%, 37%, 29%, 12% and 22%, respectively over SW₀. Application of phosphorus and nano zinc fertilizer significantly (p≤0.05) increased the maize biomass yield, root length and availability of phosphorus, potassium, magnesium and zinc in soil. These findings suggested that brackish water upto EC 8 dS m^-1 with phosphorus and zinc fertilizer is recommended for winter and summer crops in coastal saline areas.

Abstract
The medicinal properties and economic value of Labisia pumila (Kacip Fatimah) make it a significant cultivation crop. Despite the promising use of the tissue culture propagation technique in enhancing the growth of L. pumila, current research findings are limited to the nursery stage. Hence, this study was performed to assess the growth performance of tissue culture plantlets of L. pumila over 30 months of cultivation period in a mixture of soil media. In-vitro plantlets were subjected to the acclimatisation stage in sphagnum peat and coir fibre media for 24 weeks (6 months). This was followed by the growth phase in a cultivation bed containing a mixture of topsoil and organic soil for 24 months. The growth parameters, including plant height, leaf area, and root length, were evaluated, while soil samples were taken for soil analysis and heavy metal detection. Results indicate distinct growth patterns during the cultivation periods and soil properties. After the 6-month acclimatisation phase, L. pumila exhibited early growth with varying degrees of vigour in the sphagnum peat and coir fibre media. By the end of the 30-month growth phase, substantial variations in growth performance were recorded, demonstrating the favourable conditions for sustained growth in soil mixture with improved soil properties. The growth performance also increased significantly, with 5.61 times taller plants, 22.14 times larger leaf areas, and 100% root growth. Remarkably, rutin was the only flavonoid compound detected in the plant extract, which is known to possess robust pharmacological properties. Overall, this study underscores the significant influence of soil properties on the growth trajectory of tissue culture plantlets of L. pumila over extended cultivation periods.

Abstract
The overreliance on synthetic nitrogen fertilizers in rice cultivation has raised growing concerns about environmental degradation and soil health, particularly in intensive farming areas such as the Mekong Delta of Vietnam. The study was carried out to isolate, identify, and evaluate nitrogen-fixing endophytic bacteria from rice plants (Oryza sativa L.) as a sustainable alternative for biofertilizer development. Root, stem, and leaf tissues of rice were collected from fields in Kien Giang Province and subjected to surface sterilization and culturing on nitrogen-free media. The study results demonstrated that: (1) Eight endophytic bacterial strains were identified through 16S rRNA sequencing, including Burkholderia vietnamiensis, Pantoea vagans, Enterobacter mori, Gluconacetobacter sacchari, and Rahnella aquatilis. (2) All isolates demonstrated nitrogen-fixing capacity, and several exhibited additional plant growth-promoting (PGP) traits such as phosphate solubilization and phytohormone production. (3) Quantitative assays revealed fixed-nitrogen levels ranging from 0.024 to 0.091 mg N mL⁻¹. These native diazotrophs revealed strong ecological compatibility and potential for integration into sustainable rice production systems in the Mekong Delta, supporting reductions in synthetic nitrogen input and improvements in soil fertility.

Abstract
Saline water intrusion and long-term upland soils are the main difficulties in pomelo cultivation today. Thus, this study aimed to evaluate the influences of salinization and the age of upland soil on the morphological and chemical characteristics of soil in pomelo orchards. The upland soils from 5 years to 10 years were classified as Hapli Gleyic Fluvisols. Moreover, after 8 years of saline water intrusion, the salinity did not affect soil pH and EC any longer, but still reduced soluble P content and cation exchange capacity. For toxins, the salinization reduced Fe²⁺ but increased Al³⁺ concentration. The pH_KCl decreased according to the age of upland soil in Giong Trom, while the contents of organic matter, NH₄⁺, and Fe²⁺ toxicity reduced according to the age of upland soil in Chau Thanh and Giong Trom. Although after 8 years of salinization, the soil properties did not significantly change compared to the non-salinized case, prevention from salinization to pomelo orchards to ensure pomelo yield was an essential priority.

Abstract
Crude oil pollution severely impacts the chemical, biological, and physical properties of agricultural soil. This study, evaluated the bioremediation potential of Lentinus subnudus and Calocybe indica mushrooms in decontaminating crude oil-polluted soil from Ahoada East (AES), Rivers State, Nigeria. Soil samples from contaminated and uncontaminated sites served as experimental and control groups, respectively. Using a 2×2 factorial arrangement in a Completely Randomized Design, replicated three times, the experiment involved overlaying 200 grams of soil samples with 100 grams of mushroom spawn and 250 grams of sterile sawdust, with data collected at four-week intervals for three months. Analysis revealed that both mushroom species significantly reduced Polycyclic Aromatic Hydrocarbons (PAHs). The Lentinus subnudus decreased Benzo(G,H,I)Perylene by 77.60% at week 4 and Benzo(B)fluoranthene by 50.06% at week 12, while Calocybe indica achieved reductions of 96.37% and 52.62%, respectively. Heavy metal residues in the soil were also reduced, with Lentinus subnudus decreasing CU residue by 25.13% and Calocybe indica by 78.94% at week 12. The bacterial population increased by 95.83% and 36.14% at weeks 8 and 12 in dilution 3 with Calocybe indica, while fungal population increased by 41.25% at week 8 using Lentinus subnudus. The PAH-utilizing bacteria decreased by 62.5% at week 8 with Calocybe indica. Both mushrooms effectively mycoremediated contaminated soils, with Calocybe indica showing more consistency than Lentinus subnudus.

Abstract
To better understand the carbon (C) sequestration process of Acacia hybrid plantations in Song Hinh District, Phu Yen Province, Vietnam; this study was carried out to explore the distribution of C stocks among various biomass components and soil depths in three A. hybrid stands of different ages (3, 6, and 9 years old). The results showed that: (1) The amount of C stored in the biomass of trees, understory vegetation (shrubs and herbs), and litter on the forest floor increased with stand age. (2) The amount of C stored in tree biomass accounted for 79.20% of the total C stored in biomass. Other biomass C components (understory plants and litter on the forest floor) accounted for < 12% of the total C stored in biomass. (3) The soil organic C storage of 3-, 6-, and 9-year-old A. hybrid forests were 81.95, 103.60, and 140.78 Mg ha^-1, respectively. Soil organic C stocks decreased continuously with increasing soil depth. (4) Total ecosystem C storage increased with plantation age, 119.35, 169.92, and 272.11 Mg ha^-1, respectively, of which more than 60% was stored in the soil. Our results suggest that the large-scale planting A. hybrid plantations has a high potential for C sequestration during forest development in the study site.